update beta api

Author: mgamis-msft

packages/communication-react/review/beta/communication-react.api.md

@@ -5758,6 +5758,8 @@ export interface VideoGalleryStrings {
     pinParticipantMenuItemAriaLabel: string;
     screenIsBeingSharedMessage: string;
     screenShareLoadingMessage: string;
+    screenShareStartedAnnouncementAriaLabel: string;
+    screenShareStoppedAnnouncementAriaLabel: string;
     spotlightLimitReachedMenuTitle: string;
     startSpotlightVideoTileMenuLabel: string;
     stopSpotlightOnSelfVideoTileMenuLabel: string;